Stapling machine and method of forming staples



April 7, 1970 A. E. cAlRATTl 3,504,337

STAPLING MACHINE AND METHOD OF FORMING STAPLES Filed April 24. 1968 4 Sheets-Sheet 2Lv .B7 HG2 C d e? /7 FR/V575,

April 7, 1970 A. E. CAIRA-rrl 3,504,337

STAPLING MACHINE AND METHOD OF FORMING STAPLES Filed April 24, 1968 4 Sheets-Sheet 2 37M, www# April 7, 1970 A. E. cAlRATTl 3,504,837

STAPLING MACHINE AND METHOD OF FORMING STAPLES Filed April 24. 1968 l 4 Sheets-Sheet 5 9 Wap/wens.

A. E. cAlRA-rTl 3,504,837

STAPLIIING vACHINE AND METHOD OF FORMING STAPLES April 7, 1970 y Filed April 24. 1968 4 Sheets-Sheet 4.

FIGB

United States Patent O ABSTRACT OF THE DISCLOSURE A stapling machine for forming and driving staples formed from a band of cut wires in which the forming block has retractable portions which are gradually retracted 4by the cut wires or staples as they are being formed by means contacting said cut wires outwardly from the bend between the leg and crown portion of the staple lbeing formed.

This invention relates in general to stapling machines, and in particular, to a stapling machine of the retractable anvil tape having staple forming means mounted on the anvil holders to form cut wires into staples at the time a staple is driven.

Stapling machines utilizing straight cut wires to increase the magazine capacity are old in the art. In the past, such stapling machines utilized the driving blade or means movable with and attached to the driving blade to form a staple in a position rearwardly of the staple which is being driven.

One of the principal objects of the present invention is to provide a forming die connected with the anvil holders of a retractable anvil stapling machine. Another object is to provide for the formation of staples by means of a rolling motion and formation over a period of time instead of the past quick formation by moving a die vertically downwardly and sliding the die against the leg portions formed on the staple. Another object is to permit a construtcion in which the staple may be overformed t compensate for the inherent spring-back of the metal or any bowing of the cut wire, so that the formed staple legs are truly perpendicular to the staple crown. Another object is to provide in such a stapling machine a driving blade which does nothing except drive staples and which has no staple forming mechanism connected to said blade itself. Another object is to provide a construction in which the staple itself, as it is being formed, retracts the pushers slidably mounted on the forming block. Another object is to provide for the start of the formation of a staple before the driving Iblade contacts the staple to be driven, so as to lock the roll of cut wires against any rearward movement. The roll of cut wires is pre-vented from rearward movement by the formed staple which is ready to be driven, and thereafter, by a partially formed staple. This construction eliminates the necessity of a spring loaded member or roller which biases the strip of cut wires downwardly to prevent rearward movement of the roll or strip. Another object is to provide a construction in which any `wear occurs on the staple itself, because the partially formed staple moves the pusher, which is hardened tool steel, rearwardly as the staple is being formed. In the past, a vertically movable hardened steel die moved the pusher rearwardly resulting in wear between said parts.

These and other objects and advantages will become apparent hereinafter.

The present invention is embodied in a stapling machine having therein a plurality of cut wires hinged together in roll form, the anvil holders having retractable anvils and forming dies thereon for bending the outer portions of cut wires around a forming block to form 3,504,837 Patented Apr. 7, 1970 staple legs, said partially formed staple legs moving pushers rearwardly during the formation thereof, said staple legs adapted to be ibent more than The invention is also embodied in a method of forming such staples.

This invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed. In the accompanying drawings which form part of this specification and wherein like numerals and symbols refer to like parts wherever they occur:

FIG. 1 is a longitudinal central cross-sectional View of a hand operated stapling machine embodying the present invention, with a power unit being shown in dotted lines,

FIG. 2 is a top plan view thereof,

FIG. 3 is a view of the front shell assembly showing the stapling mechanism and the forming dies connected to the anvil holders,

FIG. 4 is a view of the rear shell assembly showing the front portion of the forming block,

FIG. 5 is an exploded perspective view of a forming block embodying the present invention,

FIG. 6 is a top plan view of the assembled forming block.

FIG. 7 is a side elevational view thereof,

FIG. y8 is a fragmentary elevational View of the stapling mechanism, the left half` showing the anvil in its fully actuated or lower position and the right half showing the anvil in its fully retracted or upper position and showing the cut wire,

FIG. 9 is a fragmentary view showing the forming blade as it contacts the cut wire, and

FIG. l() is a fragmentary View showing the forming blade as it bends the cut wire downwardly about 45.

Referring now to the drawings in detail, it will be seen that the embodiment of the invention which has been illustrated comprises a stapling machine M with a removable roll of cut wires W therein. The stapling machine M has a casing comprising a front housing 1 and a rear housing 2 with a stapling mechanism 3 therebetween. The front housing 1 is provided with a penetration control 4. These parts are similar in construction and operation to the equivalent parts shown in U.S. Schafroth Patent No. 2,897,502 dated Aug. 4, 1959.

The front housing 1 has a rear face 5 with a flat wear plate 5a connected thereto. The rear housing 2 has a front face 6. The stapling mechanism 3 is mounted in the casing between the housings 1 and 2 and is actuated by an operating lever 7 connected thereto at 8, the forward end of said operating lever 7 being suspended on a pivot pin 9 near the bottom of a link 10 which is free to pivot on a pin 11 secured to a handle casing 12 having a handle 13 with a handhole 14 in its upper portion. The 0perating lever 7 is connected to a yoke 15 and links 16 having anvil holders 17 at their lower ends for holding retractable anvils 18 and forming dies or blades F. The anvils 18 and the forming blades F are connected to the anvil holders 17. Springs 16a are connected between the links 16 and pins in the upper portion of the front housing 1. The front housing 1 is provided with a penetration control 4 comprising a cam 19, a follower 20 with a pivot pin 21 therein and a shaft 22, with a wing nut 23 thereon for causing the pivot pin 21 to move up or down to control the penetration depth of the anvils 18. The foregoing parts are similar in construction and operation to those shown and described in Schafroth Patent No. 2,897,502.

The housings 1 and 2 are connected to each other and to a base plate 24 by screws 25. A roll 26 of cut wires W is positioned rearwardly of the housings 1 and 2 and above the base plate 24. The stapling mechanism 3 includes a stape driving blade 27 in what shall be called position No. 1, with a guide plate 28 rearwardly of the driving blade 27 to guide the same in what shall be called position No. 2. The rear housing 2 is provided with a central horizontal hold down plate 29 secured to the rear housing 2 by a screw 30 rearwardly of the guide plate 28 to hold down the central portions of the cut wires W as they enter the stapling mechanism 3.

The machine M is designed to receive a roll of cut wires W connected by tape T over their top surfaces. The roll 26 is adapted to be positioned within a magazine 31 having a bottom 32, an upper bottom or ramp 33 which the cut wires contact, side walls 34 and 35, and inwardly extending side flanges 36 which prevent the cut wires from moving upwardly away from the ramp 33 when the machine M is being carried. The magazine 31 has a cover 37 hinged at the rear on a pin 38. The cover 37 has a tab 39 struck therefrom. The pin 38 has a spring 40 therearound to force the cover 37 rightwardly toward one side wall 34 so that a pin 41 at the forward edge 42 of the cover 37 is biased into a hole in the side wall 34 to retain the cover 37 in a closed position. A strip of cut wires issues from the roll 26 and moves forwardly on the ramp 33 and under the side iianges 36 and hold down plate 29, being guided by the side `walls 34 and 35.

Each cut wire W has a crown or central portion 43 with two end portions 44 which form the legs 45 of a staple S. The edges 4'6 of each cut wire W are pointed and form the points of the staple S. Each staple S has a bend or curve 47 between the crown 43 and the legs 4S. The cut wires W are hingedly secured together by tape T extending over a portion of their crowns 43.

A forming block 4S, as best shown in FIG. 5, is made from a number of stamped parts` The forming block 48 comprises a support block 49 of mild steel., an upper plate 50 with downturned side anges 51, a forward forming plate 52 of hardened tool steel with sloping sides 53 forming notches 54 therein, two slidably mounted pushers 55 biased forwardly by springs S6, and a bottom member 57 having two upstanding stops 58 at its forward portion which are in line with the driving blade 27 to prevent cut wires from being driven before they are formed into staples. The upper plate 50 is connected to the support block 49 by suitable mean-s, such as a pin 59 and a screw 60, which also extend through the ramp 33. The forming plate 52 is connected to the support block 49 by suitable means, such as pins I61 and a screw 62. The upper plate 50 is also provided with a downturned rear flange 63 which acts as a rear stop for the springs 56 which extend into holes 64 in the pushers 5S. The pushers 55 are slidably mounted in the cutout portions 65 of the support block 49 and are held in such position by means of the downwardly extending anges 51 on the upper plate 50. Each pusher 55 has a sloping forward or arcuate cam A66 which is contacted by a cut wire as its end portion 44 is bent downwardly to form a staple leg 45. During his bending, which exceeds 90, the staple legs 45 move the pusher 5S rearwardly the thickness of one staple. The pushers 55 have a vertical front wall 67, which is normally u-sh with the front face 68 of the forming plate 52 and a sloping surface 69 which is normally positioned opposite to the sloping sides 53 on the forming plate 52. The vertical front wall 67 normally abuts against the stops 58. The forming block 48 arrangement permits the ends of the cut wires W to be bent more than 90 (FIG. 8) so that the legs are truly vertical when the forming die F is removed and the inherent spring-back in the metal moves the legs. Should the spring-back cause the legs to be diverging when the staple is formed after the forming die F is pivoted away, the diverging legs 45 will contact the sloping surfaces 58a on the stops 58 and be made vertical as the driving blade 27 drives the staple downwardly. The forming plate 52 is provided With beveled portions 68a to direct the legs 45 downwardly should the staple tend to pivot as it is being driven.

Referring to FIG. 8, the forming blades F and the anvils 18 are secured to the anvil holders 17 by the pins 70 and screws 71, which secure the three parts together. The forming blade F in its upper position is provided with a lower horizontal surface 72 and a curved portion 73 which extends into a slanted surface 74 having an inner radius or curved portion 75 at the inner end. As the anvils 18 are rotated downwardly, the lower surfaces 72 contact the outer end portions 44 of the cut wire W (F IG. 9) and bends them over the upper edge of the forming plate 52. This is done gradually and not instantaneously as in prior machines, so that there is no immediate resistance encountered which requires a great deal of extra force. As the lanvils 18 are rotated to their lower position, the slanted surfaces 74 contact the end portions 44 (FIG. 10) until the anvils 1S get to their lowest position (FIG. 8, left portion) at which time the curved inner portion 75 forces the formed staple leg 45 inwardly beyond 90 into the notches 5.4 so that when the forming blade F is removed, the natural spring-back of the metal causes the staple legs 45 to be perpendicular to the central crown 43.

The formation of the staple legs 45 begins prior to the time when the driving blade 27 contacts the already formed staple in position No. l.

The roll of cut wires W may be of any number desired, but in a hand operated machine, comprises about 1000 cut wires because of their weight. In a power operated machine, which is not lifted or manually operated by the operator, the roll of cut Wires may be 5000 or even more. To load a roll into the magazine 31, the cover 37 must lirst be opened. This is done by grasping the tab 39 with the foreiinger and the side wall 35 with the thumb to move the tab 39 leftwardly against the action of the spring 40 thereby removing the pin 41 from the hole in the side wall 34 and allowing the cover 37 to be pivoted upwardly. A new roll of cut wires can then be inserted so that its free outer end extends up the ramp 33 and under the side flanges 36 until the rst cut wire abuts against the stops 58. The cover 37 is closed by moving it toward the side wall 35 against the action of the spring and rotating it forwardly and downwardly until the pin 41 is in alignment with the hole in the side wall 34. The tab 39 is then released thereby allowing the pin 41 to enter the hole and be retained therein because of the force of the spring 40. In this position, the roll or clip of cut wires can be moved rearwardly. To prevent this, the handle 13 should be moved downwardly to cause the rst cut wire W to be formed into a staple S. Since the roll 26 has tape thereon to secure the cut wires to one another, once the first cut wire has been formed into a staple, the roll 26 cannot be moved rearwardly.

In operation, and in order to drive a staple, the handle 13 is depressed. As the handle moves downwardly, the anvil holders 17 begin to rotate downwardly until the forming blade F contacts the cut wire in position No. 2 to begin bending its end portions 44 around the upper corners 76 of the forming plate 52, whose top edge is ush with the upper surface of the ramp 33. After the partially formed legs 45 are bent downwardly a few degrees they contact the arcuate cam surfaces 66 on the pushers 55 to force said pushers 55 rearwardly against the action of the springs 56. At about this time, the driving blade 27 contacts the rst staple, which has already been formed and moved to position No. 1, to drive it downwardly. This first staple is driven downwardly and is clinched in the manner described in previous patents such as Schafroth U.S. Patent No. 2,897,502. As the driving blade 27 moves downwardly, the pushers 55 are moved rearwardly until their front faces 68 are behind the legs 45 of the number 2 staple which is being formed. When the handle 13 is moved upwardly, the springs 56 move the pushers 55' forwardly so that their front faces 67 push the legs 45 of the staple just formed into position No. l under the driving blade 27 ready to be driven. In position No. 2, the forming blades F first contact the end portions 44 of the cut wire W with their surface 72, then their curved portions 73, their slanted portions 74, and finally their inner curved portions 7S (FIGS. 8-10) to bend the legs 45 more than 90 into the notches 54 formed by the sloping sides 53, which slope inwardly about 10 from a vertical line. The upper corners 76 have a radius of about 0.031.

It will be Seen that, unlike prior devices, the forming blades F gradually, and not instantaneously, move the staple legs 45 downwardly around the upper edge 76 of the forming plate 52. This results in easier operation, since in a typical commercial size only about one-half pound more pressure need be exerted as the staple is being formed. Previously, a definite resistance point was encountered because the staple was formed instantaneously by sliding movement `of a downwardly moving die. This arrangement avoids the necessity of close tolerances between forming dies and the forming blade F and also permits the staple to be over-formed (i.e. over 90), thereby permitting the staple legs 45 to spring back to a 90 position due to the inherent spring-back of the material.

In the prior systems, staples were often under-formed because of this spring-back and diicult points were encountered in the actuation of the machine due to the instantaneous formation of the staple in position No. 2.. This also created much friction, and the springs 16a in the machine had to be aided by hand because of this friction in order to retract the mechanism.

The present device moves the forming blade F with the anvil holders 17, which allows a staple to be formed by a rolling motion and over a period of time. It further permits over-forming the staple to compensate for the inherent spring-back. When the parts return to their upper or normal position there is no friction on the return stroke because the forming blade F immediately moves away from the formed staple and does not slide on the staple legs 45. The driving blade 27 does nothing except drive a staple. There is no wear between the forming blade F and the pushers 55 because the staples, which are mild steel, move the hardened steel pushers 55 rearwardly. If the handle 13 is moved partially downwardly, a staple is partially formed and this prevents the roll or strip of cut wires from moving rearwardly without the necessity of any hold-down bar or roller.

The present invention is shown in a hand operated machine operated by the operating lever 7 shown in FIG. 1. However, if desired, a power cylinder may replace the lever 7 in the well known manner, as shown in the dotted lines in FIG. 1. This power cylinder must be attached to suitable sources of compressed air.

This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. In a stapling machine for forming and driving staples formed from a band of cut wires connected together in side by side relation, said stapling machine having a casing with a stapling mechanism therein of the retractable anvil type, said stapling mechanism having a driving blade and a pair of anvils therein, each of said anvils concams to move said pushers rearwardly when said anvil holders are pivoted downwardly prior to and during the driving of a staple which has previously been formed from the cut wire.

2. The combination set forth in claim 1 wherein said means connected with the anvil holders comprises forming blades which contact the outer ends of the cut wire to be formed into a staple before the driving blade contacts the previously formed staple which is to be driven.

3. The combination as set forth in claim 2 wherein said forming blades each have a lower surface, a slanted surface, and an inner radius portion adapted to contact said cut wire end one after the other during the downward movement of the anvils to gradually bend the cut wire into a staple and to bend said cut wire ends more than and into a notch in said forming block to compensate for the spring-back in the cut wire.

4. The combination set forth in claim 1 wherein said forming block has notches therein and said staple legs are held in the notches of said forming block when the driving blade is in its lowest position after driving a previously formed staple.

5. The combination set forth in claim 2 wherein said forming blades and said anvils are secured to said anvil holders by the same securing means.

6. The combination set forth in claim 1 wherein the cam on each pusher comprises a curved surface on the forward end portion of said pusher, so that the cut wire ends gradually force each pusher rearwardly as they are being bent into substantially perpendicular position to the crown of the staple.

7. The combination set forth in claim 1 wherein the forming block comprises a support block with a forming plate connected to the forward end thereof, and wherein said forming plate is provided with inwardly extending notches for receiving the staple legs as they are bent more than 90 from the original position at the ends of the straight cut wires.

8. The combination set forth in claim 7 wherein each pusher is provided with a cut-out portion inwardly of said carn to permit said cam to move forwardly into the plane of the forming plate opposite to said notches therein.

9. The combination set forth in claim 1 wherein the forming block is provided with stop means at its forward portion for stopping the band of cut Wires from moving forwardly beyond the forming plate without first having been formed into a staple.

10. The combination set forth in claim 1 wherein said pushers have vertical front walls which are ush with the front face of the forming block and are in contacting relation to upstanding stops connected to and positioned forwardly of said forming block.

References Cited UNITED STATES PATENTS 1,192,680 7/1916 Pentz 72-702 X 1,241,863 10/1917 Lewis 227-92 X 1,625,958 4/1927 Reed 83 1,675,080 6/1928 Allen 83 2,195,889 4/1940 Maynard 85 X 2,964,751 12/1960 Lang 83 X 2,987,725 6/1961 Heilman 227-85 3,177,697 4/1965 Over 72-702 X 3,224,657 12/1965 Zike 227-136 X 3,279,673 10/ 1966 Schafroth 227-85 WAYNE A. MORSE, IR., Primary Examiner U.S. Cl. X.R. 

